Single-joint front jaw of a safety binding for skis having vertically adjustable hold-down arms

ABSTRACT

A front jaw of a ski binding has a central face to support the front edge of a boot sole and hold-down arms which engage over the sole at both sides of the boot toe and are supported by a movable cover on a jaw body that is swingable laterally, relative to a mounting plate fixed to the ski, against the force of resilient holding means enclosed and protected within the jaw body and cover. According to one feature, the cover is adjustable vertically relative to the jaw body to adapt the location of the hold-down arms to the thickness of the boot sole. According to another feature the cover is releasibly biased downward so that the boot sole can be freed safely from the hold-down arms by movement against the force applied through the cover.

United States Patent [1 1 Brunner 51' Jan. 16, 1973 [54] SINGLE-JOINT FRONT JAW OF A SAFETY BINDING FOR SKIS HAVING VERTICALLY ADJUSTABLE HOLD- DOWN ARMS [76] Inventor: Rudolf Brunner, Wankstrasse 23,

Baldham, Germany 22 Filed:- Dec. 30, 1970 21 Appl.No.: 102,786

[30] Foreign Application Priority Data Dec. 30, 1969 Germany ..P 19 65 409.2

52 us. Cl. ..2s0/11.3s T 51 Int. Cl ..A63c 9/00 [58] Field ofSearch; .....280/11.35 T

[56] References Cited UNITED STATESPATENTS 3,149,854 9/l964 Marker.. ..280/1 1.35 T 3,298,703 l'/1967 Marker ..280/] 1.35 T

3,462,165 8/1969 Brunner ..280/ll.35 T

Primary Examiner-Leo Friaglia Assistant ExaminerRobert R. Song Att0rneyAlbert C. Johnston [57} ABSTRACT A front jaw of a ski binding has a central face tosupport the front edge of a boot sole and hold-down arms which engage over the sole at both sides of the boot toe and are supported by a movable cover on a jaw body that is swingable laterally, relative to a mounting plate fixed to the ski, against the force of resilient holding means enclosed and protected within the jaw body and cover. According to one feature, the cover is adjustable vertically relative to the jaw body to adapt the location of the hold-down arms to the thickness'of the boot sole. According to another feature the cover is releasibly biased downward so that the boot sole can a be freed safely from the hold-down arms by movement against the force applied through the cover.

19 Claims, 14 Drawing Figures PATENTEDJAN 16 I975 sum 1 ur 3 N M mR m8 v l 0 0 U R OM M ATTo EY PATENTEDJAH 16 1915 3,711.10?

SHEET 2 [IF 3 INVENTOR R UOOLF BRUNNER ATTO EY PATENTED JAN 1 6 I975 SHEET 3 BF 3 FIG.I4

INVENTOR R U DOLF BRUNNER ATTOR Y SINGLE-JOINT FRONT J AW OF A SAFETY BINDING FOR SKIS HAVING VERTICALLY ADJUSTABLE HOLD-DOWN ARMS This invention relates to a single-joint front jaw of safety bindings for skis, of a kind having a central supporting face for the front edge of the sole of a ski boot, a pair of hold-down arms extending over and engaging 'with the boot sole at both sides of the toe-cap, and a jaw body that is swingable laterally relative to a base member mounted on the ski when a laterally directed force is exerted on one of said hold-down arms against the force of a resilient holding means inside the jaw body.

Vertical adjustability of the hold-down arms is required to provide for fitting them over the boot sole at all times, that is, in case of differing thickness of the boot sole and possibly also in case of differing levels of the mounting of the front jaw, so that the front portion of the sole will be firmly held down on the ski and vertical play between the upper side of the sole and the hold-down arms prevented. 1

lt is known, for example, to provide a portion separate from the rest of the jaw body as a support member carrying the hold-down arms as well as the supporting face for the front edge of the boot sole, such portion being mounted through the transverse groove connection enabling it to be set in a fixed position at any of various levels on the jaw body. It is also known to arrange a corresponding support member vertically adjustably by means of screws on the jaw body at the back side of the front jaw carrying the hold-down arms. Finally, it is known to render the whole jaw vertically adjustable by either just mounting it on washers differing in thickness or holding it on a screw bolt about which the body of the jaw is rotatable into positions of different levels. I I

All these known means for vertical adjustment are either relatively expensive or have the disadvantage that a skier whose foot stands in the binding cannot effect adjustment by just manipulating the binding without removing the foot therefrom.

Accordingly, his one object of this invention to provide for simple vertical adjustment of the hold-down arms to be readily effected from above even with the binding being connected to the'foot.

tial operational parts of the jaw located inside its body, such as a notched cam, a ball spring-pressed into the notch of the cam, and the pivotal mounting of the body so that it is swingable laterally with respect to a part to be secured to the ski, remain, therefore, substantially unaffected by the provisions for vertical displaceability.

The vertically displaceable cover supporting the hold-down arms according to the invention can also be made to support the central supporting face of the front jaw, as by forming this face as a rigid part of the cover extending below the hold-down arms.

According to one way of carrying out the invention, the jaw cover is made vertically adjustable with respect to the jaw body in a direction strictly parallel to the pivot axis of the front jaw. In this case a dish-shaped casing member, or cover, can be easily so fitted on the jaw body that no openings for ingress of water or dirt are formed by the vertical adjustment, thus sufficiently complying with the requirement that the entire interior of the front jaw be protectively enclosed against impairment by external influences.

According to a second way of carrying out the invention, the cover is hingedly connected with a front portion of the jaw body, at a location remote from the hold-down arms. This manner of construction is based on recognition of the fact that the range of displacement required for vertical adjustment of the hold-down arms needs not be very large, since the thickness of boot soles is standardized to a large extent; sothe adjustment can be effected by swiveling over a small angle. In order to avoid access of dirt or water to the movable parts of this type of front jaw, the part of the jaw body supporting the notched cam, the springpressed ball and the pivot about which the front jaw is laterally swingable is; preferably made so that it con-- stitutcs a capsule, or casing, also enclosing these parts. lt is understood, however, that such an additional capsulation could also be provided for the first embodiment above mentioned, for increased safety.

The minor disadvantage of the stated second way,

7 consisting in that the hold-down arms do not extend strictly horizontally at all levels, is by far outweighed by its advantages. A substantial advantage consists in that thecover can be biased downward about its pivot axis I on the front portion of the jaw body so that a swing-up It is afurther object of this invention to provide for a I simple construction using a part of the jaw provided for the other purposes also as the support member of the hold-down arms.

Another object is to provide forsafe release-of the boot toe from the front jaw by upward movement of the sole and the hold-down arms against a predetermined force that normally holds the armsdownward insole binding position. A

For achieving these objects according to the invention it is provided that the. hold-down arms aresupported by and extend backwardly from a cover which is displaceable vertically relative to said laterally swingable body of the front jaw, and which preferably has the form of a casing shell fitting over the jaw body. Since a cover or a casing shell shielding the interior of the jaw from above is required in any event for the protection of the parts inside the jaw against outside influences, the'invention does not require any substantial additional expenditure for vertical adjustability. The, essenmovement of it can even be used for release of the jaw from the boot toe in caseof a backward fall of the skier, inasmuch as then the hold-down arms together with the cover will swing open upwardly against the biasing force. The body of the jaw remains unaffected by such release unless a lateral release of the jaw is also effected during the backward fall.

Another substantial advantage of applying the holddown arms to a vertically displaceable cover becomes evident when, according to the invention set forth in my copending application Ser. No. 808,545, filed Mar. 19, 1969 the angle enclosed by the two fulcra of the hold-down arms at the toe-cap and the supporting face of the jaw is adjustable to the particular boot size by having the two hold-down arms form integral parts of a common rigid structural member adjustable in the longitudinal direction of the jaw with respect to the supporting face which remains fixed. In this case the supporting face can be a fixed part of the laterally swingable jaw body, and the hold-down arms can either, be

made longitudinally adjustable with respect to the cover or, on thecontrary, can be connected with the cover in a completely rigid manner and the wholecover mounted on the body so that it is longitudinally adjusta- The above, and other objects, features and ad- I vantages of the invention, will be apparent in the following detailed description of illustrative embodiments which is to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a longitudinal sectional view of a front jaw according to this invention;

FIG. 2 is a sectional view of a vertical adjustment screw staggered in parallel with respect to the view of FIG. 1, with a portion being broken away;

FIG. 3 is a horizontal sectional view of the jaw according to FIG. 1 below the hold-down arms;

FIG. 4 is a sectional view above the hold-down arms, parallel to the view of FIG. 3; I

FIG. 5 is a top plan view of thejaw of FIGS. 1 to 4;

FIG. 6 is a longitudinal sectional view, similar to that of FIG. 1, of a modified embodiment of a front jaw according to the invention;

FIG. 7 is a horizontal sectional view, similar to that of FIG. 3, ofthe frontjaw of FIG. 6;

FIG. 8 is a top plan view of the front jaw of FIG. 6;

FIG. 9 is a rear view of the front jaw of FIG 6, showing the side of the jaw carrying the hold-down arms;

FIG. 10 is a longitudinal sectional view of a third em- I bodiment ofa frontjaw according to this invention;

FIG. '1 l is a horizontal sectional view of the front jaw ofFIG. 10; J

. FIG. 12 is a cross-sectional view of the front jaw of FIGS. 10 and 11; and

FIGS. 13 andl4 are, respectively,.a top plan view and a rear view of the frontjaw of FIGS. 10 to 12.

' Each of the three illustrated embodiments of the invention is provided with a mounting plate 10 or 10a attachable to the ski by screws which extend through holes 12 shown in FIGS. 7 and 11. However, the jaw can also be fastened on the ski in a different way-as indicated by the modified top plan view of FIG. 5.

Avertical supporting column 16 is rigidly secured to mounting plate .10 by a rivet 14, by welding, or the like, said supporting column, or post, being provided with a cross bore 18 extending in the longitudinal direction of the jaw and slidingly receiving a sleeve 20. Above the cross bore thesupporting column 16 continues as an upright sleeve portion 22 which, in the embodiment according to FIG. 1, extends to the upper side of the jaw in the manner illustrated. In the embodiments of FIGS. 6 and 10 a similar post or support column 16a has a cross bore 18a receiving a slidable sleeve 20a and continues above that sleeve within the jaw only, providing a short upright sleeve portion 22a. 7

Within the upright sleeve portion 22 or 22a an adjusting pin 26 (FIG. 1) or 26a (FIGS. 6 and 10) is rotatably arranged so as to be rotatable about its axis from above by engagement of a coin or a screw driver with an elongated slot 28 provided in its head. Adjusting pin 26 in FIG. 1 is provided with a circumferential groove 30 into which a pin 32 extends from the sleeveshaped portion 22 of supporting column 16 so that the adjusting pin is rotatable about its axis but not vertically displaceable. In FIGS. 6 and 10, a similar adjusting pin 26a has an annular shoulder 26b engaged by an annular flange 70, hereinafter further described, so as to hold thisadjusting pin against vertical displacement.

The lower end of adjusting pin 26 or 2611 is provided with an eccentric extension 34 or 34a engaging in a spiral recess 36 or 36a in the circumferential surface of sleeve 20 or 20a, so that that sleeve assumes different longitudinal positions within the cross bore of the supporting column 16 or 16a, depending on the angular position of the adjusting pin.

The front end of sleeve 20 or 20a is substantially closed by an end wall 38 or 38a which serves as a forward bearing surface for a compression spring 40 arranged within the sleeve. The backward end of this spring bears against a ball 42 held slidably in a projecting forked backward end 44 or 44a of the sleeve. The forked free end of the sleeve holds the ball 42 against displacement laterally relative to the sleeve 20 or 20a in each of the possible longitudinal positions of the sleeve with respect to the cross bore 18 or 18a. Hence, the force with which the spring 40 presses the ball 42 into the notch 48 ofa cam plate 52 can beselected by a corresponding angular adjustment of adjusting pin 26 or 26a.

The support column 16 or 16a, sleeve 20 or 20a encompassing the spring 40 and ball 42 and adjusting pin 26 or 26a are, in each of the three embodiments shown, adapted to be rigidly mounted on the ski so as to remain fixed relative thereto except upon displacement of the ball in the sleeve or upon longitudinal adjustment of the sleeve. These parts constitute the rigidly mountable support means of the front jaw. On the other hand,

the jaw also comprises body means which are swingable laterally about an axis formed by the support means, in-

cluding an enclosure-forming part, or body member, A

'or.A', which is mounted pivotally on the support column 16 or 16a so that this part can be swung out laterally aboutthe axis of the column. The column 16 or 1 6a thus forms the single-joint pivot post of the front jaw.

In all three embodiments of the invention the laterally swingable part A or A is rigidly connected extending transversely at the back of the jaw. The cam plate has oppositely directed steeply sloped faces 48 which define a centrally disposed notch or cup normally engaged by and limiting lateral movement of the ball 42, each of which faces merges into a cam surface 50 of lesser inclination followed by a curved cam surface 46 of increasing inclination. In case of a sufficient lateral force on the front jaw from'the toe of the boot bound thereto, the laterally swingable part A or A of the jaw body and the notched cam plate 52 or 52a thereon swing out laterally, with displacement of the ball 42 forwardly against the force of spring 40 by the thrust of the inclined faces 48, S0 and 46 of the cam plate.

' Furthermore, in all three embodiments the cam plate 52 or 52a is securedto a lower panel 54 or 540 of the laterally swingable part A or A, which panel has a bearing portion 56 or 56a fitted about the supporting column 16 or 16a, in a manner slightly differing in the various embodiments, and has near the front of the jaw an upwardly extending wall portion 58 or 58a that can be a bent-up arm 58 as shown in FIG. 1 or an arm 107 fixed to a bent-up front wall 58a of a box-like enclosure as shown in FIGS. 6 and 10.

In the arrangement of FIG. 1 the laterally swingable part A is mounted on supporting column 16 by means of lower panel 54 only, for which purpose that panel is provided with a special sleeve-shaped bearing extension 56, and the lower panel 54 terminates rearwardly in a straight rear edge at 60. In contrast thereto, in the embodiments shown in FIGS. 6 and 10, the lower panel 54a also has an upwardly bent extension 62 at the rear end which, together with an upper panel 64 formed opposite'to the lower panel and having downturned end extensions 65 and 66 and corresponding side walls, forms a capsule or enclosure A for the cam plate and the spring-pressed ball assembly of the jaw body. This enclosure is guided on supporting column 16a in the simple bearing hole 56a of the lower panel, through which column 16 extends, and by an upwardly extending sleeve portion 68 of upper panel 64, which portion terminates in an annular flange 70 overlying shoulder 26b and embracing adjusting pin 26a so as to constitute an upper bearing for the swingable enclosure A' The cam plate 52 or 52a is connected in fixed relation to the laterally swingable body part A or A, as by means of rivets 72 or 72a fixing it to the lower panel 54 or 54a.

In all three embodiments, a supporting face at the back of the jaw forms an abutment against which the front edge of a ski boot rests when in the binding. In the first embodiment (see FIG. 3) the supporting face 76 is slightly convex, while the supporting face 76a in the I second and third embodiments (see FIGS. 7 and 11) is concave.

ln'each embodiment, at a location above and to both sides of the supporting face 76 or 76a, two hold-down arms 78 diverge rearwardly in a configuration which serves to centralize the boot by a substantially punctiform abutment laterally against both sides of the toecap.

In all three embodiments the hold-down arms are an integral part of a mounting member therefor which is adjustable relative to the supporting face 76 or 76a in the longitudinal direction of the jaw, so that the distance between the two diverging hold-down arms 78 at the supporting face 76 or 76a, or where the arms will engage against the toe-cap of the boot above the boot sole, is adjustable so as to adapt to the particular boot size of the skier.

In the embodiment of FIG. 1 a dish-shaped casing or cover 80 encompassing the laterally swingable body member A of the jaw has depending side walls which fit over the forward and backward parts of that body member at 58 and 60. A horizontal slot 82 is provided in the back wall of this casing or cover, and a flat forward extension 84 of the hold-down arms 78, formed integrally with them, is displaceable through slot 82 in the longitudinal direction of the jaw with the upper surface 86 ofthe flat extension bearing against the lower surface of the top of casing or cover 80. In a forward tongue portion of the flat extension 84 an elongated slot 88 is provided (FIG. 4), and an adjustment screw 90 extending through the casing or cover top from its upper side passes through the slot 88 and then into engagement with a lock nut 92 mounted non-rotatably in a recess of extension 84. Thus, the hold-down arms 78 then re-tightening the screw 90. The flat extension is guided laterally in a recess between spaced surfaces 94 (FIG. 4) on the under side of the cover 80, which surfaces prevent lateral displacement of the hold-down arms relative to the cover 80 and other laterally swingable parts of the front jaw.

In the embodiments of FIGS. 6 and 10, wherein the supporting face 76a is constituted by the rear wall of the laterally swingable enclosure or capsule A of the jaw body, the hold-down arms 78 are immovably secured to the cover member 80a, being formable as an integral part thereof, and longitudinal adjustability of them is provided by mounting the entire cover for displacement longitudinally relative to the underlying body of the jaw.

For this purpose the hold-down arms 78 in the embodiments of FIGS. 6 and 10 are formed integrally with a short depending back wall a ofthe cover, which extends downwardly and is supported upon the backward end of the laterally swingable enclosure or capsule A of the jaw body. At the front of the jaw a depending front wall 102 is provided an cover 80a, ex-

tending somewhat further downward than wall 100a v and being spaced somewhat forwardly from the front end of capsule A. An adjusting screw 104 extends through wall 102 and is screwed into a tapped hole 106 in an arm 107 projecting up from the forward end wall 58a of the capsule.

By simply turning the screw 104 with a coin or screwdriven engaging in its head 130, the cover 80a and integral hold-down arms are adjusted backward or forward to the desired longitudinal position of the arms relative to the toe-supporting face 76a. Such movement of the cover80a relative to the upright adjusting pin 26a is permitted by an elongated slot 108 provided in that cover. Although some snow or dirt may be able to pass through the elongated cover slot 108, this is not critical since the essential movable parts of the jaw are protected inside the walls of the laterallyv swingable capsule or enclosure A of the body. If desired, an additional lamellar or stretchable sealing means could be provided'between pin 26a and the walls of elongated slot 108.

Furthermore, in all three illustrated embodiments of the front jaw the level of the hold-down arms 78 is ad justable vertically relative to the mounting plate 10 and the laterally swingable parts at A and A.

To this end in the embodiment of FIG. 1, the casing or cover 80 fitting over the body member A in a dishlike manner is displaceable vertically on the upright sleeve portion 22 0f supporting column 16, and vertical adjustment is effected by means of two screws 110 actuable from the upper side of cover 80. These screws pass through openings in the cover 80 and the flat extension 84 and are each screwed into a threaded sleeve 1 l2 rigidly connected with the lower panel 54 and cam plate 58 of the laterally swingable body A. Moreover, at the front side of the jaw the cover 80 has front wall portion 116 extending downwardly outside the bent-up arm 58 of lower panel 54, to a location close to mounting plate 10. This front wall 1 16 carries a locking screw 118 that projects through it and through an elongated slot 119 in arm 58 and engages with a rectangular nut 120 which is held against rotation in-a channel formed by back turned flanges 122 of arm 58. Upon loosening of the screw 118, the dish-shaped cover 80 with arms 78 thereon can be slid vertically to any desired height above the base plate 10, or the top surface of the ski, and can then be locked in place by re-tightening of the screw 118.

While in the embodiment of FIG. 1 the vertical adjustment is effected parallel to the axis of the supporting column 16, the embodiments of FIGS. 6 and 10 provide for vertical adjudgment of the hold-down arms by a swiveling of cover 80a about its connection with the jaw body'at the front of the jaw. For this purpose,

the longitudinal adjustment screws 104 are each provided with a ball-shaped head 130 seating in a complementary ball-shaped recess 132 of the extension 102 of cover 80a. The ball-shaped screw heads and recesses form a universal joint which permits the cover 80a to be pivoted about the screw heads 130, with a corresponding vertical displacement of the back end of cover 80a and the arms 78 thereon.

In the embodiment of FIGS. 6 to 9, vertical adjustment of the height of the arms 78 can be effected by means of two adjustment screws 140 each of which has an internal thread screwed onto a threaded pin 141 hingedly fixed at its lower end to a part of the capsule member A, such as to the the upper panel 64 thereof.

In the embodiment of FIGS. 10 to 14, the vertical displaceability of the cover is utilized to provide an additional factor of safety to the skier. To this end, in approximately the locations of the threaded pins 141 and hollow screws 140 of FIGS. to 9, tension springs 154 are stretched between the, cover 80a and a part of member A, such as the lower panel 54a thereof, so that these springs will normally hold the cover and arms 78 in their hold-down position but, in case of; a backward fall of the skier, will allow the arms 78 and cover 800 to swing up vertically about the pivot axis at the front of the jaw until the hold-down arms 78 are released from the toe of the skiers boot.

In this embodiment the adjustment screws 140 of FIG., 6 are replaced by two adjustment screws 150 which, as will be evidentfrom FIG. 12, are each threaded into an internal thread of a sleeve 152 having an external thread onto which the upper end of a tension spring 154 is screwed. The tension springs extend to lower panel 54a and are hooked to it by means of the hook-shaped spring ends 156.

In the embodiment of FIGS. -14, the normal position of the hold-down arms is defined by the tension springs themselves, at the location where their windings abut against one another. The vertical adjustment or height of the hold-down arms can be varied by turning the two adjustment screws 150, as they can be screwed into the sleeves 152 to varying distances. Partitions 160 (FIGS. 11 and 12) form vertical recesses in rear end portions of the space between lower panel 54a and It is preferred that hold-down arms 78 be supported I rigidly on cover member as explained in detail in the foregoing. On the other hand, in the scope of invention also such known constructions are included which are provided with hold-down arms swingably mounted at front jaws and biased into normal positions by the tension of a spring means. It should be noted with respect to such a construction that the hold-down arms can, but need not, hold the toe of the boot. This holding function can be given in some arrangements by the central supporting face only, and then the capability of the hold-down arms to swing in opposite lateral directions is only needed to release the boot from the front jaw in case that the jaw body itself swings laterally. A preferred construction of this type shows the feature that said hold-down arms are each supported swingably on said cover member and biased into normal positions by spring means.

Although illustrative embodiments of this invention have been described in detail herein, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention.

What is claimed is:

1. In a single-joint front jaw of a safety binding for a ski, including support means rigidly mountable on the ski, body means swingable laterally about an axis on said support means and, carried by said body means, a central supporting face for the front'edge of the sole of a ski boot and a pair of holddown arms adapted to extend over said sole and engagewith both sides of the toe-cap of the boot, said support means and said body means having coacting parts normally holding said face and said arms in binding position yet resiliently displaceab'le forlateral swinging of said body means about said axis under a laterally directed force exerted on one of said hold-down arms, said body means including a lowerbody member swivelled on said support means and a cover member secured over the top thereof, the improvement wherein said members are interconnected by. means enabling said cover member to be displaced vertically relative to said body member and said hold-down arms are supported rigidly on said cover member, said interconnecting means including means hingedly connecting a front portion of said cover member to a part on the front of said body member so that the back of said cover member and said arms thereon can be swung upwardly relative to said body member. 7 v

2. A front jaw according to claim 1, said cover member having the form of a casing shell with depending side walls fitting down over sides of said body member.

3. A front jaw according to claim 1, said body member comprising panels forming a substantially closed capsule enclosing said coacting parts and swiveled on an upstanding element of said support means.

4. A front jaw according to claim 1, said interconnecting means comprising at least one adjustment screw extending through and actuable from above said cover member in the region of said hold-down arms, each said screw being threadedly engaged with a retainer thereof secured to said body member, so that said cover member may be displaced vertically by turning said at least one screw, and further comprising at the front of the jaw remote from said hold-down arms a fastening screw extending through a front wall portion of said cover member and securing the same to a rigid part extending upwardly on said body member.

5. A front jaw according to claim 4, said front wall portion being turnable about a horizontal axis on said fastening screw so that the back of said cover member and said hold-down arms are displaceable vertically by a swinging movement thereof.

6. A front jaw according to claim 1, said cover member having a front wall portion extending downwardly over a rigid part extending upwardly on the front of said body member and being hingedly connected therewith by at least one adjusting screw extending through said front wall portion and threadedly engaging with a retainer on said part, so that said cover member may also be displaced longitudinally by turning movement of said at least one screw for adjustment of the relative position of said hold-down arms'and said supporting face, said face being formed by a back wall portion of said body member.

7. A front jaw according to claim 6, the head of each said adjusting screw and an adjacent part of said front wall portion having complementary formations which define a universal joint.

8. A front jaw according to claim 1, said interconnecting means further including means yieldably biasing said cover member and said arms thereon downwardly toward said body member yet enabling said arms and cover member to be swung upwardly by the skiers boot to release the boot in case of a fall of the skier lengthwise of the ski.

9. A front jaw according to claim 8, said interconnecting means further including at least one adjusting screw extending vertically through said cover member and operable from above it and each threadedly engaging a retainer secured to a part of said biasing means so that the binding position of said arms may be easily adjusted by turning said at least one adjusting screw.

10. A front jaw according to claim 1, said supporting face being formed by a back wall portion of said body member, said interconnecting means further including tension spring means biasing the back of said cover member downwardly toward said body member yet enabling said arms and cover member to be swung upwardly by the skiers boot to release the boot in case of a fall of the skier lengthwise of the ski.

11. A front jaw according to claim 10, said spring means including at least one coiled spring disposed vertically on a lower portion of said body member and for each such spring an adjusting screw extending through a backward portion of said cover member and threadedly engaging a retainer on an upper part of the spring so that the binding position of said arms may be easily adjusted by turning said at least one adjusting screw.

12. A front jaw according to claim 11, said retainer being an internally and externally threaded sleeve engaged by its external thread with upper coils of said spring.

13. A front jaw according to claim 11, said body member comprising panel means forming a substantially closed capsule enclosing said coacting parts and swiveled on an upstanding part of said support means, and further forming an upwardly open chamber for an aforesaid coiled spring in each backward corner of said body member, an upright partition of said chamber being part of the walls of said capsule.

14. In a single-joint front jaw of a safety binding for a ski, including support means rigidly mountable on the ski, body means swingable laterally about an axis on said support means and, carried by said body means, a central supporting face for the front edge of the sole of a ski boot and a pair of hold-down arms adapted to extend over said sole and engage with both sides of the toe-cap of the boot, said support means and said body means having coacting parts normally holding said face and said arms in binding position yet resiliently displaceable for lateral swinging of said body means about said axis under a laterally directed force exerted on one of said hold-down arms, said body means including a lower body member swivelled on said support means and a cover member secured over the top thereof, the improvement wherein said members are interconnected by means enabling said cover member to be displaced vertically relative to said body member and said hold-down arms are supported rigidly on said cover member, said body member comprising a lower panel lying beneath said coacting parts and swivelled on an upstanding element of said support means, said panel having a rigid member extending upwardly from the front thereof, said cover member having a rigid front wall portion extending downwardly over said rigid member and secured thereto by parts of said interconnecting means.

15. A front jaw according to claim 14, saidcover member having at the back thereof a rigid wall portion extending downwardly below said hold-down arms and constituting said central supporting face.

16. A front jaw according to claim 15 said back wall portion having a slot therein above said supporting face, said hold-down arms being integral with a support portion extending horizontally forward through and displaceable longitudinally in said slot, and coacting means on said support portion and said cover member, operable .from the upper side of the latter, for releasably yet rigidly holding said support portion to said cover member in any desired longitudinal disposition of said arms relative to said face.

17. A front jaw according to claim 16, said holding means comprising a longitudinal slot in said support portion, an adjusting screw extending through said cover member and said longitudinal slot, and a lock nut engaging with said screw beneath said longitudinal slot.

18. A front jaw according to claim 14, said rigid member having a vertically elongated slot therein, and a fastening screw extending through said front wall portion and said slot and engaging a lock nut to lock said cover member securely, yet releasably for vertical adj ustment, relative to said body member. 

1. In a single-joint front jaw of a safety binding for a ski, including support means rigidly mountable on the ski, body means swingable laterally about an axis on said support means and, carried by said body means, a central supporting face for the front edge of the sole of a ski boot and a pair of hold-down arms adapted to extend over said sole and engage with both sides of the toe-cap of the boot, said support means and said body means having coacting parts normally holding said face and said arms in binding position yet resiliently displaceable for lateral swinging of said body means about said axis under a laterally directed force exerted on one of said hold-down arms, said body means including a lower body member swivelled on said support means and a cover member secured over the top thereof, the improvement wherein said members are interconnected by means enabling said cover member to be displaced vertically relative to said body member and said hold-down arms are supported rigidly on said cover member, said interconnecting means including means hingedly connecting a front portion of said cover member to a part on the front of said body member so that the back of said cover member and said arms thereon can be swung upwardly relative to said body member.
 2. A front jaw according to claim 1, said cover member havIng the form of a casing shell with depending side walls fitting down over sides of said body member.
 3. A front jaw according to claim 1, said body member comprising panels forming a substantially closed capsule enclosing said coacting parts and swiveled on an upstanding element of said support means.
 4. A front jaw according to claim 1, said interconnecting means comprising at least one adjustment screw extending through and actuable from above said cover member in the region of said hold-down arms, each said screw being threadedly engaged with a retainer thereof secured to said body member, so that said cover member may be displaced vertically by turning said at least one screw, and further comprising at the front of the jaw remote from said hold-down arms a fastening screw extending through a front wall portion of said cover member and securing the same to a rigid part extending upwardly on said body member.
 5. A front jaw according to claim 4, said front wall portion being turnable about a horizontal axis on said fastening screw so that the back of said cover member and said hold-down arms are displaceable vertically by a swinging movement thereof.
 6. A front jaw according to claim 1, said cover member having a front wall portion extending downwardly over a rigid part extending upwardly on the front of said body member and being hingedly connected therewith by at least one adjusting screw extending through said front wall portion and threadedly engaging with a retainer on said part, so that said cover member may also be displaced longitudinally by turning movement of said at least one screw for adjustment of the relative position of said hold-down arms and said supporting face, said face being formed by a back wall portion of said body member.
 7. A front jaw according to claim 6, the head of each said adjusting screw and an adjacent part of said front wall portion having complementary formations which define a universal joint.
 8. A front jaw according to claim 1, said interconnecting means further including means yieldably biasing said cover member and said arms thereon downwardly toward said body member yet enabling said arms and cover member to be swung upwardly by the skier''s boot to release the boot in case of a fall of the skier lengthwise of the ski.
 9. A front jaw according to claim 8, said interconnecting means further including at least one adjusting screw extending vertically through said cover member and operable from above it and each threadedly engaging a retainer secured to a part of said biasing means so that the binding position of said arms may be easily adjusted by turning said at least one adjusting screw.
 10. A front jaw according to claim 1, said supporting face being formed by a back wall portion of said body member, said interconnecting means further including tension spring means biasing the back of said cover member downwardly toward said body member yet enabling said arms and cover member to be swung upwardly by the skier''s boot to release the boot in case of a fall of the skier lengthwise of the ski.
 11. A front jaw according to claim 10, said spring means including at least one coiled spring disposed vertically on a lower portion of said body member and for each such spring an adjusting screw extending through a backward portion of said cover member and threadedly engaging a retainer on an upper part of the spring so that the binding position of said arms may be easily adjusted by turning said at least one adjusting screw.
 12. A front jaw according to claim 11, said retainer being an internally and externally threaded sleeve engaged by its external thread with upper coils of said spring.
 13. A front jaw according to claim 11, said body member comprising panel means forming a substantially closed capsule enclosing said coacting parts and swiveled on an upstanding part of said support means, and further forming an upwardly open chamber for an aforesaid coiled spring in each backward corner of said body membeR, an upright partition of said chamber being part of the walls of said capsule.
 14. In a single-joint front jaw of a safety binding for a ski, including support means rigidly mountable on the ski, body means swingable laterally about an axis on said support means and, carried by said body means, a central supporting face for the front edge of the sole of a ski boot and a pair of hold-down arms adapted to extend over said sole and engage with both sides of the toe-cap of the boot, said support means and said body means having coacting parts normally holding said face and said arms in binding position yet resiliently displaceable for lateral swinging of said body means about said axis under a laterally directed force exerted on one of said hold-down arms, said body means including a lower body member swivelled on said support means and a cover member secured over the top thereof, the improvement wherein said members are interconnected by means enabling said cover member to be displaced vertically relative to said body member and said hold-down arms are supported rigidly on said cover member, said body member comprising a lower panel lying beneath said coacting parts and swivelled on an upstanding element of said support means, said panel having a rigid member extending upwardly from the front thereof, said cover member having a rigid front wall portion extending downwardly over said rigid member and secured thereto by parts of said interconnecting means.
 15. A front jaw according to claim 14, said cover member having at the back thereof a rigid wall portion extending downwardly below said hold-down arms and constituting said central supporting face.
 16. A front jaw according to claim 15 said back wall portion having a slot therein above said supporting face, said hold-down arms being integral with a support portion extending horizontally forward through and displaceable longitudinally in said slot, and coacting means on said support portion and said cover member, operable from the upper side of the latter, for releasably yet rigidly holding said support portion to said cover member in any desired longitudinal disposition of said arms relative to said face.
 17. A front jaw according to claim 16, said holding means comprising a longitudinal slot in said support portion, an adjusting screw extending through said cover member and said longitudinal slot, and a lock nut engaging with said screw beneath said longitudinal slot.
 18. A front jaw according to claim 14, said rigid member having a vertically elongated slot therein, and a fastening screw extending through said front wall portion and said slot and engaging a lock nut to lock said cover member securely, yet releasably for vertical adjustment, relative to said body member.
 19. A front jaw according to claim 14, said support means having an upright sleeve portion extending above said coacting parts, there being a rotatable pin for adjusting the force of said parts, which extends upwardly through said sleeve portion so as to be operable from above the jaw, and said cover member having formed therein a cylindrical opening the wall of which fits and is slidable vertically on said sleeve portion. 